Some types of integrated circuits are completely custom designed, where each of the electrical devices in the integrated circuit is specifically selected for the custom design, and the integrated circuit is laid out in a customize manner. Such integrated circuits tend to have a relatively large amount of overhead associated with them. For example, there is a large amount of design work involved in producing such a customized integrated circuit. Further, customized mask sets and tooling are required to produce the integrated circuits. When it is expected that a very large number of the integrated circuits will be sold, then it can be cost effective to invest in the overhead associated with the customized integrated circuit, as the overhead can be paid off over a large number of the integrated circuits.
However, there are other applications where such a large number of sales of the integrated circuit is not expected. In these applications, it tends to be cost prohibitive to design the integrated circuit from scratch, so to speak, and to invest in completely customized mask sets and tooling, because there will not be enough of the integrated circuits fabricated to justify such a large investment.
For these smaller-number applications, a different type of integrated circuit is commonly used, called an application specific integrated circuit, or ASIC. ASICs are designed using standardized design elements, or modules, which are combined in a desired configuration to support the intended application. In other words, the design of the integrated circuit is application-specific, as the name implies. ASICs tend to be much cheaper to design and produce than custom integrated circuits, because the standardized design elements have already been designed. Further, mask designs already exist for the design elements. Thus, there is a tremendous head-start on the design process, and ASICs therefore tend to be much less expensive to fabricate than completely customized integrated circuits.
Unfortunately, because the standardized design elements of an ASIC can be combined in a variety of ways, the cost savings associated with standardization have typically not been extended to the packaging used for the ASICs, or the printed circuit boards to which they are ultimately mounted. For example, because different ASICs—even those using similar standardized modules—tend to be laid out with the standardized modules in different configurations, the package substrate and printed circuit board typically require a different configuration for each such design. Thus, all the costs of a completely customized package design tend to be incurred, even when using standardized modules in an ASIC design.
What is needed, therefore, are package substrate and printed circuit board designs with standardized elements for use with an ASIC, which designs can help reduce the costs associated with designing packages and circuit boards for different ASICs.